it's not that easy. i think you need to use the lasso and select the person, copy and paste him/her in new file, and work with the background from there. however, the lasso tool does not always filter out everything so you may need to use zoom. i'm not an expert and haven't really done it so i can't tell you, but that's what i'd try.
by the way, whatever happened about the 2am AOL calls?